It's Sunday and therefore it's time for a 'How To'. Many people feel annoyed at people who think that everyone around them is less smart than they are. If you want to ruin their false notions, or if you want to become that person, being pretentious is helpful.
Today's 'How To' is book quoting. Remember all those classics that you have sitting on your bookshelf? Well, start referencing them in conversation. Depending on your situation, you may want to reference different books. For example, in many hoity toity circles Jane Austen is just a romance writer so referencing her books wouldn't be very pretentious. However, in non-hoity toity circles referencing Jane Austen means you like classy writing. You just need to feel it out to determine what books you want to reference.
Once you have determined what books you want to reference, read them/read parts of them. Memorize the book title and author. You can't be pretentious if you don't remember the source of your reference.
Once you have your selected books read, start practising comparing normal life to your books. You will soon be able to throw book references into any conversation, making yourself one step closer to acting/being pretentious.